Microchip PoE to USB-C® Power and Data Adapter - Review

Table of contents

RoadTest: Microchip PoE to USB-C® Power and Data Adapter

Author: stevesmythe

Creation date:

Evaluation Type: Power Supplies

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: No exact comparators but there are other PoE adapters available for different applications and hardware.

What were the biggest problems encountered?: None

Detailed Review:

Introduction

The Microchip PoE to USB-C Power and Data Adapter is a self-contained unit that receives 48V power and a data connection from a suitably-configured PoE router or switch and delivers power (up to 60W) and/or data (up to 1,000 Mb/s) through its USB-C connector.

 

My aims in this review are to explain what PoE is, how you can use it, and compare the Microchip PoE to USB-C Power and Data Adapter with other PoE options for your devices.

 

Thanks to element14 for providing the opportunity to test it. As I don't have any suitable test equipment for this type of device (apart from a multimeter), I decided to carry out a "consumer-style" test, rather than a lab-based one.

 

What is PoE?

Power-over-Ethernet ("PoE") is a networking feature defined by the IEEE 802.3af, 802.3at and 802.3bt standards. PoE lets Ethernet cables supply power to network devices over the existing data connection.

 

In May 2020, I Roadtested a Raspberry Pi PoE HAT and, in the process, explained a bit about the benefits and applications of PoE.

 

Although the IEEE 802.3bt standard existed at that time, I was not aware of any devices that used it. The Microchip adapter is the first such product that I have come across.

 

Who is it aimed at?

The marketing materials for the Microchip PoE to USB-C Power and Data Adapter suggest very clearly that it is intended to allow a "kiosk PC" to be operated from a single PoE-enabled network cable. By "kiosk PC", I think they mean the sort of small, low-powered PC, such as an Intel NUC that is used in information kiosks (often with a touch-screen) in public places. Normally those devices would need a power connection and also a network or Internet connection. Long network cables are relatively low-cost and would allow the kisok PC to be up to 100m or 328ft from the network switch. In contrast, USB-C cables can only be a few (<4) metres in length if used to transmit data, so the Microchip PoE to USB-C Power and Data Adapter would allow such a kiosk to be installed in relatively remote locations  where there is no easy access to mains power.

 

What is included?

Apart from the box, and a cloth bag to store the device when not in use, all you get is the device itself, a very short (30cm) USB-C cable and a brief "Quick Start Guide".

Although the cable is short, it has a thumbscrew on one end to keep it inserted into the Microchip device and an indicator light on the connector at the other end to show an active power connection.

The Quick Start Guide should be all that you need to get going, as the device is intended to be "Plug and Play". Specifically, the LAN7800 chip should be recognised by the device to which you connect the Microchip adapter and the appropriate driver for it should be installed automatically. However, the Microchip documentation says "Linux® may require driver installation in case the LAN7800 Ethernet controller is missing". I didn't find this to be the case on any device I tested.

 

What else do I need?

To make use of this device, you will either need a PoE switch or a standalone PoE injector. The amount of power that the Microchip device is able to provide will depend on what kind of PoE source you have. I connected the Microchip device to my TP-Link TL-SG1008P IEEE 802.3at Gigabit switch, which can provide a maximum of 30W to a single port or 64W in total to all 8 ports. The Microchip device also worked quite happily on my D-Link DES-1008PA (IEEE 802.3af) switch whose power output is limited to a maximum of 15.4W on a single port. In practice, the type of switch or PoE injector you need will be determined by the power requirements of the device that you are intending to connect to the Microchip adapter. If you are just connecting a Raspberry Pi 4 or a low-power CCTV camera, you will be fine with a IEEE 802.3at switch or PoE injector but if you are looking to power a PC or higher-power device, you will need a IEEE 802.3bt switch or PoE injector. Microchip recommend the Microsemi PD-9601GC PoE injector, which costs over £100 in the UK, although slightly lower-cost alternatives are available from other vendors. The cheapest 802.3bt switch I could find in the UK was the Zyxel GS1350-6HP 5-Port Smart Managed Gigabit PoE++ switch, of which only two ports are rated at 60W output (the other three being 15.4W max). At the time of writing, these were available for around £140 in the UK. Switches capable of providing 90W per port are upwards of £200.

 

Use cases

1. Kiosk PC

I tested the device on a Dell XPS 15 7590 laptop running Debian with the KDE Plasma desktop. The screenshots show that the Microchip device provides both power and network connectivity.

As my TP-LINK switch only provides a maximum of 30W per port, which is less than the Dell needs to maintain full battery charge, a warning message is seen.

         

I booted up the Dell with Windows 10 and noted that the power connection (as indicated by the green LED on the USB-C cable) was not detected by Windows. It appears that Windows thinks there is no power if the battery is still discharging, unlike Debian which acknowledges the power deficiency.

 

For reference, the Dell comes with a 130W power supply.

 

I also tested the Microchip device on an HP ENVY laptop running Windows 10. For reference, the HP laptop comes with a 65W power supply. As with the Dell running Windows 10, although the green LED on the USB-C cable lit up (indicating a power connection), the laptop stayed on battery power.

In terms of network connectivity, the LAN7800 USB 3.0 to Ethernet adapter was recognised as a Gigabit network adapter.

My testing suggested to me that, connected to an 802.3bt switch or PoE injector, the Micochip device would be able to power a small PC or laptop and this was confirmed by fellow RoadTester Gough Lui, who bought a suitable PoE injector. Even though my switch had insufficient power to meet the PCs' needs, the Microchip adapter did provide both laptops with a wired network connection which they wouldn't otherwise have, in the absence of an RJ45 port.

 

2. Raspberry Pi PoE

I connected the Microchip adapter to the Raspberry Pi 4's USB-C power socket and, after enabling USB-OTG (by adding otg_mode=1 to config.txt), it powered up fine. However it didn't work when I tried one of the original Raspberry Pi 4s. This is not a fault with the Microchip PoE-USB-C adapter - the original Raspberry Pi 4 had its USB-C connector wired incorrectly and, although it worked with a "dumb" USB-C cable (including the official Raspberry Pi 4 power supply) which just supplies power, it wouldn't power up with a (smart) USB-C cable that uses the USB-C configuration channels to detect the type of device being connected. For more information, see, for example, this article on Hackaday.

 

The Raspberry Pi Foundation released a second version of the Pi 4 ("Rev 1.2") which fixed the problem. To find out if your Raspberry Pi 4 is Rev 1.2 or later (and will therefore work with the Microchip PoE-USB-C adapter), load the Terminal and type "cat /proc/cpuinfo". Press Enter and at the bottom of the screen it will show your Raspberry Pi model details including Revision number.

 

Because I didn't have an actual "kiosk PC" available to test, nor an IEEE 802.3bt switch or PoE injector, I decided to make a miniature kiosk computer by adding a Pimoroni Hyperpixel touchscreen to the Raspberry Pi 4. The photo shows "eth1:" connected to my 802.3at switch.

 

When I RoadTested the official Raspberry Pi PoE HAT last year, I looked at several other PoE options for the Raspberry Pi and concluded that the official PoE HAT was a good choice for most applications. The Microchip PoE to USB-C adapter has the advantage of not blocking the GPIO pins so, for a Raspberry Pi kiosk computer with a touchscreen mounted on those pins, it might be a better choice albeit at five times the price.

 

One application I had in mind for the Microchip adapter was to power my Raspberry Pi Wildlife Camera. As mentioned in my Raspberry Pi POE HAT Roadtest, it was easy for me to run an IP55 Ethernet cable out into the garden as I already have a PoE CCTV camera on my garage roof. With a bit of fiddling, I had managed to fit the Raspberry Pi into the Naturebytes Wildlife Cam Case with the PoE HAT on top using some longer standoffs. Unfortunately, although the Microchip adapter itself fits nicely into the case, because the Ethernet and USC-C sockets are at opposite ends of the Microchip device, there is not enough room inside the case to connect the cables.

 

3. Mobile phone charger

The Microchip device was able to charge my Moto G6 phone. Sadly, this phone does not appear to support OTG Ethernet, so I was not able to enjoy a wired Ethernet connection. Although it works as a charger, it would be an expensive way to charge your phone! It would have been more impressive if my phone supported OTG Ethernet as I could then enjoy a fast network connection even when there is no WiFi or 4G.

 

Conclusions

The Microchip PoE to USB-C Power and Data Adapter costs around £100 in the UK. Assuming you have a suitable PoE switch or injector, or don't mind spending another £100 or more in getting one, the Microchip adapter would allow you to provide power and a network connection to a small PC or other network equipment from a single Ethernet cable. Even if you only have the cheaper and more common IEEE 802.3at switch, the Microchip device can provide Ethernet connectivity if your PC lacks an RJ45 socket but does have a spare properly-configured USB-C port (as is increasingly the case).

 

The Microchip adapter is an "indoors only" device and doesn't come with an IP rating. For outdoor applications (such as CCTV cameras), it would therefore need to be mounted in a suitable weatherproof container. Due to the design, where there is a connector on each end, the IP-rated container would need to be at least 20cm x 8cm x 4cm interior dimensions, which might limit your choices.

 

At the time of writing (August 2021), the Microchip PoE to USB-C Power and Data Adapter appears to be the only USB-C PoE adapter available that is capable of powering a small PC (up to 60W). Although there is a very small market for this particular type of device, if that is what you are needing, then the Microchip PoE to USB-C Power and Data Adapter is certainly recommendable. It is well-designed and reasonably rugged.

 

If you need a PoE adapter for a Raspberry Pi 4 (Rev 1.2 or later), the Microchip PoE to USB-C Power and Data Adapter will work, but it is more expensive and takes up more space than other options and, due to the limitations of the Raspberry Pi 4's USB-OTG controller, is limited to a maximum of 480Mb/s, compared to Gigabit speed available if you use the official Raspberry Pi PoE HAT.

 

Overall, I rated the device 59/60, dropping a single point because the documentation is a little sparse and doesn't mention the indicator LED on the supplied USB-C cable or explain that it lights up when the connected device is drawing power. Otherwise, I couldn't fault the device; it is simple to use and does what it says it will do. The Microchip PoE to USB-C Power and Data Adapter fills quite a small niche at the moment but, as IEEE 802.3bt switches become more common and drop in price, it will come into its own and have a head start on any future competition.

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